| 摘要 |
The present invention relates to a process for the production of aqueous polyurethane-polyurea dispersions for which A) firstly A1) primary and/or secondary monoamines or diamines are reacted with A2) cyclic carbonates which contain precisely one hydroxy group, where the molar ratio of A1) and A2) is such that in the case of monoamines A1) the theoretical ratio of the entirety of the primary and secondary amine groups to the cyclic carbonate groups is from 0.8 to 1.2 and in the case of diamines A1) the theoretical ratio of the entirety of the primary and secondary amine groups to the cyclic carbonate groups is from 1.8 to 2.2, and A3) in the case of diamines A1) the remaining primary and secondary amine groups are reacted with compounds which bear precisely one functional group which reacts with primary or secondary amines in an addition reaction, in such a way that there are no resultant isocyanate-reactive groups, where the molar amount of A3) is such that the theoretical ratio of the entirety of the theoretically remaining primary and secondary amine groups after reaction of A1) and A2) to the amine-reactive groups in A3) is from 0.8 to 1.2, where the reaction with A3) can take place after, at the same time as or prior to the reaction with A2), B) then a polyurethane prepolymer containing NCO groups is produced by reaction of B1) polyisocyanates with B2) polymeric polyols and/or polyamines with number-average molar masses of more than 400 to 8000 g/mol and B3) optionally low-molecular-weight compounds with number-average molar masses of 17-400 g/mol selected from the group consisting of mono- and polyalcohols, mono- and polyamines and aminoalcohols and B4) optionally isocyanate-reactive, ionically or potentially ionically hydrophilizing compounds and/or isocyanate-reactive non-ionically hydrophilizing compounds and B5) the reaction products of A), C) the prepolymer from B) is dispersed in water, and D) optionally the remaining free NCO groups of the prepolymer are reacted with isocyanate-reactive monoamines, polyamines, hydrazine and/or hydrazides, where the molar amount of these is such that the theoretical ratio of the isocyanate-reactive NH groups to the NCO groups is from 0 to 1.2, where the reaction D) can take place to some extent or else entirely prior to or during the dispersion step C). |
